Counduit



A ug. 20, 1929. w. J. LEARY CONDUIT Original Filed March 3l, 1927 Dx byPatented Aug. 20, 1929.

UNITED STATES PATENT OFFICE.

WILLIAM J. LEARY, OF CHICAGO, ILLINOIS.

CONDUIT.

Application led March 31, 1927, Serial No. 180,047. Renewed January 17,1929.

This invention relates to a conduit and more particularly to afabricated conduit which is acid and alkali resistant and therebyenables the conduit to be used for conveying materials which would eatinto ordinary piping and require its frequent replacement.

The principal object of this invention is to provide a conduit or pipeconstructed of spirally wound strips of metal, the inner i strip orlining of which is of an acid and alkali resistant metal such as lead,Monel metal, brass, copper, tin, etc., and the outer strip or strips ofwhich are of steel or, .if desired, a relatively hard and durable acidand alkali resistant metal such as Monel metal, brass, copper, tin,etc., theouter strips being securely interlocked .to impart thenecessary strength and rigidity to the conduit, and the seam or jointbetween the convolutions of the lead lining being tightly and reliablysealed to insure against possible leakage ot' the material beingconveyed to the exterior steel strips.

A further airn is to provide such a fabricated conduit which isadequately insulated to prevent exchange ot' heat between the liningofthe conduit and the protecting sheath.

Further objects are to provide such piping which is light in weight,easily fabricated by continuous winding processes, and in which heavygage'and hard sheet st eel can be employed for the layer whichreinforces and supports the lining, thereby permitting of the productionof large size piping of great strength.

ln the accompanying drawings: v

Figure 1 is a side elevation ola section length of a conduitmade inaccordance with my invention, a portion of the same being shown insection. Figure 2 is an enlarged fragmentary oblique section takentransversely through the joint between the convolutions of the conduitshown -in Fig. 1. Figure 3 is a View similar to Fig. 1 but showing amodified form ot' joint. Figure 4 is an enlarged sectional view similarto Fig. 2 but showing the modified forni of joint illusti'ated in Fig.3. Figure 5 is a view similar to Figs. 2 and 4, but showing a furthermodified form of joint. Figure 6 is a fragmentaiy longitudinal sectionthrough the form of locking band shown in Fig. 5. Figure 7 is a viewpartly in elevation similar to Fig. 5, but showing the same rolled andthe attaching lugs struck out from the base thereof. Figure 8 is aperspective View of a section of the lead key which is interposedbetween the lead lining strip in all of the forms of the inventionillustrated in the drawings.

Similar reference numerals refer to like parts on each of the severalfigures.

The strips of metal used in making the conduit may vary in Width orthickness and either a single strip of metal can be used as shown in thedrawings, or a lurality of strips may be employed side y side, in whichcase the lead of the convolutions may be increased. Good practicedictates that a long spiral lead makes a much stronger and stiffer pipethan a short lead. Although a short lead may be used in Winding thestrips it is preferable to make the leads as long as possible to avoidfracturing the met-al or destroying the fibrous structure thereof, whichwould be liable to occur if the metal were crimped or bent abruptly.

The lining of the conduct is made of a strip 10 of sheet lead or othersoft acid and alkali resistant metal and is wound spirally on a mandrel.Simultaneously with the winding of the lining strip 10, a lead key 11 iswound so as to be interposed between the successive convolutions of thelining strip. This key as shown in Fig. 8 is in the form of a continuousband and the opposite sides thereof are recessed or dished inwardly asindicated at 12. When the key and lining strip are being wound, the keyis fed against the advance edge of the lining strip so that a ange 13 isformed on the advance edge of the strip, which flange lies against therecessed side l2 of thekey, and the width of the strip being wound isproportioned so that a similar flange 14 is formed at the rear edge ofthe strip against the advance recessed face 12 of the next precedingconvolution of the key strip. By this means both edges of the liningstrip are extended along opposite sides of the key strip, as shown inFigs. 1-5, and a tight joint is obtainable.

To securely unite the lining strip and the key strip and also to impartthe necessary strength and rigidity to the conduit, a metal strip 15 ofsteel or the like is wound helically over the lining strip and a lockingband 16 is wound over the spiral joint and securely locks theconvolutions together. This metal strip 15 is formed at its edges toprovide flanges 17 which lie against the outer sides of the flanges 13and 14 of the lead lining strip as best shown in Figs. 2, ,4, and 5. The

locking band 16 comprises a central portionV extending` flat flange 23and the underside of the central portion 1S is provided with a roundedridge 2e. Before being applied to the body of the conduit, the sideportions 2O are spread apart and disposed at an oblique angle to thecentral portion 18. The band is then wound over the seam and the centralportion thereof rolled down o n the upper ends of the flanges of thelining and steel strips, and at the same time the side portions arerolled flat against the periphery of the conduit, andthe inner ridges 22thereof are forced under and against the flanges 17 and the seam therebycompressed so that the lead is forced to flow and unites the flanges andkey. The locking band also provides a. joint which is as strong orstronger than the other portions of the conduit and stiffens andstrengthens the entire piece of p1 Je.

lIo prevent circumferential displacement of the locking band and also toadd to the strength and tightness of the joint, each of the steelstrips15 is provided adjacent its two ,edges with a plurality ofcircular recesses suitably formed on the outer side of the strip andspaced the entire length of the same. The locking band 1G is similarlyprovidedwith a plurality of lugs or bosses 25 spaced along the innerside of the flat flanges 23, which lugs are adapted to engage thecorresponding recesses in the steel strip. These lugs 25 are preferablystamped or punched from the locking. band, leaving correspondingrecesses 26, on the outer side thereof.

The insulation 27 is then wound on the conduit between the convolutionsof the locking band. This insulation may be of any suitable material butis preferably acid and alkali resistant and is preferably wound in theform of a strip or sheet which completely fills the space between theconvolutions of the locking band but leaves the channel 19 in the upperside of the locking band exposed.

In the next operation the sheath is wound over the insulated conduit tofinish, strengthen and protect the pipe. This sheath is preferably madeof a steel strip 28 and the adjacent edges'of the successiveconvolutions are interloclred about a core 29, but if it is desired tohave a'conduit which is acid resistantboth inside and outside, it may bemade of lead, brass, copper, etc. Different seams may be employed forthis purpose, the seams shown in Figs 1 and 2 being formed about a roundcore and being of corresponding shape, and the seams shown in Figs. 3-5

being wound around a core which is recf tangular in cross section. Inthis latter form of seam, the edges of the strip are interloclred sothat the seam is disposed on the inner side of the sheath therebyproviding a conduit having a smooth outer surface. In each of the forms,the seam is received in the channel 19 provided in the locking band,thereby materially strengthening the pipe against bending strains. Ifdesired, the seam formed by the interlocking of the edges of the sheathstrip may be soldered or brazed to the locking band so as to prevent thesheath from separating when the pipe is .cut.

In the modified form of the invention shown in Figs. 5, 6, and 7, thecentral portion 18'of the locking band is provided with a series ofintegrally formed wedge shaped lugs or teeth 30 which are spaced alongthe inner side of the same. When the locking band is rolled, thesewedges are forced into the lead key and causethe lead to flow laterallyand upwardly and securely unite the members forming the seam and providea hermetically sealed seam. These wedge shaped lugs or teeth also serveas spacers, the flanges 17 being forced against the sides of the teethwhen the locking band is rolled in place, as shown in Fig. 5, and theseteeth thereby insure a seam or joint of uniform width and strengththroughout the conduit. Inasmuch as the conduit during this opera tionis held on a mandrel, the bore or inner surface ofthe conduit is notaffected by this squeezing ofthe lead-in the seam.

This invention provides a light and inexpensive fabricated conduit forconveying acid and alkaline materials; it is strong and thoroughlyinsulated and adequately protected against injury.

I claim as my invention:

1. A conduit comprising a helically wound strip of a soft, acidresistant metal, a helically wound strip `of theV same metal arrangedbetween adjacent convolutions of said first named strip, and means forlocking said strips together.

2. A conduit comprising a helically wound strip of a soft, acidresistant'metal, a helically wound key of the same metal interposedbetween adjacent convolutions of said strip, said strip being formed atits edges to provide flanges arranged at the opposite sides of said key,and a helically wound locking band locking said flanges and keytogether.

3. A conduit comprising a helically wound strip of a soft, acidresistant metal, a helically wound key of the same metal interposedbetween adjacent convolutions of said lll) strip, said key havinginwardly dished sides, and said strip being formed at its edges toprovide flanges arranged at the opposite inwardly dished sides of' saidkey, and a helically wound locking band locking said flanges and keytogether.

4. A conduit comprising a helically wound lining strip of a soft, acidresistant metal, said lining being formed at its edges to provideflanges, a helically wound hard metal strip overlying said lining, saidouter strip being formed to provide flanges arranged adjacent theflanges of said lining strip, and a helically Wound locking bandengaging the outer sides of the flanges of said outer strip.

5. A conduit comprising a helically wound lining strip of a relativelysoft, acid resistant metal, a helically wound key of the saine metalinterposed between adjacent convolutions of said strip, said key havinginwardly dished sides and said lining strip being formed at its edges toprovide flanges arranged at t-he opposite inwardly dished sides of saidkey, a helically wound hard metal strip overlying said lining strip,said outer strip being formed to provide flanges arranged adjacent theflanges of said lining strip, and a helically wound locking bandengaging the outer sides of the flanges of said outer strip.

6. In a conduit, a helically wound lining strip of relatively softmetal, a helically Wound key of the same metal interposed betweenadjacent convolutions of said strip, said lining strip being formed atits edges to provide flanges arranged at the opposite sides of said key,a helically wound hard metal strip overlying said lining strip, saidlining strip being formed at its edges to provide flanges arrangedadjacent the flanges of said lining strip, and a helically Wound lockingband engaging the outer sides of the flanges of' said outer strip, saidlocking band being provided with an inwardly projecting portion which isforced into said key during winding of the conduit and uniting said keyand lining.

7. In a conduit, a helically wound strip of relatively soft metal, a.helically wound key of the same metal interposed between adjacentconvolutions of'said strip, and means for locking said strip and keytogether, said means including inwardly projecting portions which areforced into said key and unite said key and strip.

8. In a conduit, a helically wound lining strip of relatively softmetal, a helically wound key of the same metal interposed betweenadjacent convolutions of said strip, said lining strip being formed atits edges to provide flanges arranged at the opposite sides of said key,a helically wound hard metal strip overlying said lining strip, saidlining strip being formed at its edges to provide flanges arrangedadjacent the flanges of said lining strip, and a helically wound lockingband engaging the outer sides of the flanges of said outer strip, saidlocking band being formed with a series of longitudinally disposed,wedge shaped teeth which are forced into said soft metal key during thewinding of the conduit and unite said key and lining.

9. In a conduit, an inner helically Wound strip of metal, said stripbeing formed at its edges to provide flanges, a helically wound lockingband engaging the opposite sides of said flanges and locking adjacentconvolutions together, a helically wound insulating strip overlyin saidinner helically wound strip, a helically wound strip overlying saidinsulating strip and said locking band and forming a sheath, the stripforming the sheath being interlocked at the edges of adjacentconvolutions, and a seam thereby formed being received in a longitudinalchannel provided in said locking band.

10. In a conduit, an inner helically wound strip of metal, said stribeing formed at its edges to provide anges, a helically wound lockingband engagin the opposite sides of said flan es and locing adjacentconvolutions toget er, a helically wound insulating strip overlying saidinner helically wound strip, a helically Wound strip overlying saidinsulating strip and said locking band and forming a sheath, the stripforming the sheath being interlocked at thel edges or" adjacentconvolutions to form an inwardly extending seam which is received in alongitudinal channel provided in said locking band.

1l. In a conduit, an inner helically wound strip of metal, said stripbeing formed at its edges to provide flanges, a helically wound lockingband engagin the opposite sides of said flanges and loc ing adjacentconvolutions together, a helicaly Wound insulating strip overlying saidinner helically wound strip, a helically wound strip overlying saidinsulating strip and said locking band and forming a sheath, the stripforming the sheath being interlocked at the edges of adjacentconvolutions, and a sea-m thereby formed being received in alongitudinal channel provided in said locking band, said seam beingadapted to be connected by a fused joint with said locking band.

In testimony whereof I affix my signature.

WILLIAM J. LEARY.

